Rotary blower or gas-pump.



J. I. WILKIN.

ROTARY BLOWER OR GAS PUMP.

APPLICATION FILED A211. 16, 1907.

905,967. Patented Dec. 8, 1908.

lvii mamm I 51111011? wdg J3] dofinTm/ii/hn.

Gumm

. suiliciently to have raised the pressure of air UNITED STATESPATENT oFFIcE.

JOHN T. WILKlN, 0F CONNERSVILLE, INDIANA, Ab'blGNOR TO THE CONNERSVILLE myowna 00., OF GONNliltSVlLLli, INDIANA, CORPORATION OF lNDlANA.

ROTARY BLOWER OR G AS-PUMP.

Specification of Letters Patent.

Patented Dec. 8, 1908.

Application filed April 16, 1907. Serial No. 368,551.

To alt whom it may concern:

l3e 1t known that I, JOHN T. \VILKIN, a citlzen oi the United States, residing at Connersville, in the county of Fayette and State j blast pipe 17 where the high velocity of the of Indiana, have invented certain new and useful Improvements in Rotary Blowers or f Gas-Pumps, of which the following is a specification.

The object of my invention is to so construct the discharge passage of a gas pump, of the rotary-impeller type, as to produce a more uniform flow of air or gas in the discharge pipe and thereby obtaining to some extent a gradual compression of air within the pump.

The accompanying drawing is a partial transverse section of a pump of the two-lobed impeller type provided with my improve ment, but it is to be understood that my invention is not limited to the particular form own.

When a blower or pump takes its supply, a quantity of gas or air is inclosed between. the impeller 10 and. the cylinder 11 and when the end of lobe of an impeller passes the edge 12 of the cylinder adjacent the discharge .outlet, this quantity, which is being driven forward by the impeller, is suddenly exposed to the greater pressure or the air in the discharge pipe and this pressure in the discharge pipe produces at that time a backward tiow toward the impeller until the air, which is being to save power by j driven forward by the im cller, is raised to the pressure in the discharge pipe. This backward flow of the air in tl absorbs a considerable amount of power. in order to overcome this dilliculty i provide a doubly tapered. discharge opening, as clearly shown in the drawing, the passage beginning as nearly as possible to the paths of movement of the tips of the impellers, diminishing in diameter to a constricted tlu'oat l5, and then gradually widening, as shown at Hi to the main. pipe '17. By this means the vclocity of discl'iarge, closely :iidjaccnt the cylinder, is comparatively high, without however being increased in the main discharge pipes at a distance from the pump. As a cruise qucnce the inertia of air through the throat such that, before the liow can be rcversed by reason of the sudden release of pressure, due to the .movement of the iIHPOl. lers, the impellers will have moved forward in the blower high. enough to prevent the re discharge pipe l i l l l l l l l l l l l l f backward flow from the discharge system.

After the air has passed through the throat 15 it passes through the diffusion tube 16 which gradually increases in size to the main an is converted into pressure.

Under ordinary conditions a rotary blower is not an economical compressor because the impellers are continually subjected to the full discharge pressure but, by means of the constricted discharge throat and gradually expanding diffusion tube, I obtain a partial gradual compression of each displacement of air which becomes more effective as the speed of the blower s increased, and backward flow of the discharge is prevented.

It is to be understood that the constriction in the discharge passage must be of such character, as compared withthe velocity of outflow produced by the blower that the constriction results in such an increase of velocity, over that which would ordinarily be produced by the blower that there can not be a reversal of movement of the current in the short time during which there is a release of pressure owing to the movement of an. impeller past the discharge opening.

in practice I have found that with amachine operating against a 7 lb. pressure in the supplied system, the constriction throat between the pump and the supplied system should be such that the velocity through the throat will be about 238 feet per second whereas operation under a 6 lb. pressure in the supplied system requires approximately a velocity of about 208 feet per second in the constricted throat. The higher the pressure in the supplied system, the higher the velocity required in the throat.

I claim my invention:

1 The com bination, with a gas pump com-- prising a pair of co-acting rotary lobed impeilers producing pulsatory discharges, of a discharge passage for said pump, said dis charge having a constricted portion at a point between its beginning and its end.

2. The combination, with a gas pump comprising a pair of co-acting rotarylobed Elmpcllers producing pulsator discharges, of a discharge passage for sai pump, said discharge passage being constricted at an intermediate point and gradually widening beyond sai constriction. I

3. A gas cum com risingapairof co-acting rotary ioloe impe lers producing pulsatory discharges, of a discharge passage beginning at a oint closely adjacent the paths of travel of t e impellers and diminishing in size to a constricte throat and subsequently increasing, whereby a suflicient velocity of discharge immediately adjacent the ump is produce'd to' revent backward flow etWeen discharge pu sations of pump.

4. A gas pum comprising a pair of co-acting rotar lobe impellers producing pulsatory disc arges, of a discharge passage beginning at a oint closely adjacent the paths of travel of t e impellers and diminishlng in size to a constricted throat and subsequently increasin by a gradual taper, whereby a sufficient ve ocity of discharge immediately adjacent the pump is produced to prevent backward flow between discharge pulsations of pump.

In witness whereof, I, have hereunto set my hand and seal at Connersville, Indiana, this tenth day of April, A. D. one thousand nine hundred and seven. 4.

JOHN TI 'WiLKIN. [L. a]

Witnesses J. S. TATMAN, E. W. Ans'rnne 

